HC-05 Bluetooth Serial Module – 6 Pin with Button

HC-05 Bluetooth Module with Button

The HC-05 Bluetooth Module adds wireless serial communication to Arduino boards and other microcontrollers. It transfers UART data between your project and a compatible Bluetooth device.

The module supports both Master and Slave modes. You can also use AT commands to change its name, password, communication speed, and operating mode.

Key Features

• Bluetooth Classic wireless communication
• Supports Master and Slave modes
• UART serial interface
• Six-pin breakout board
• Onboard button for AT command mode
• Adjustable name, password, role, and baud rate
• Status LED for connection monitoring
• Compatible with Arduino and many microcontrollers

Technical Specifications

• Model: HC-05
• Bluetooth Type: Bluetooth Classic 2.0 + EDR
• Communication Protocol: UART
• Operating Modes: Master and Slave
• Board Supply Voltage: 3.6V–6V DC
• UART Logic Level: 3.3V
• Default Data Baud Rate: 9600bps
• Typical AT Mode Baud Rate: 38400bps
• Default Device Name: HC-05
• Default Pairing Password: 1234
• Typical Wireless Range: Up to 10m
• Configuration: AT commands

Pin Description

• EN/KEY: Activates AT command mode
• VCC: Connects to the board power supply
• GND: Connects to ground
• TXD: Sends serial data from the module
• RXD: Receives serial data from the microcontroller
• STATE: Provides the Bluetooth connection status

Basic Connection with Arduino

1. Connect VCC to the Arduino 5V pin.
2. Connect GND to the Arduino GND pin.
3. Connect HC-05 TXD to the Arduino RX pin.
4. Connect the Arduino TX pin to HC-05 RXD through a voltage divider.
5. Pair your device with the module.
6. Use serial communication to send and receive data.

Applications

Use the HC-05 module for:

• Arduino wireless control
• Mobile-controlled robots
• Bluetooth-controlled cars
• Wireless sensor monitoring
• Home automation projects
• Microcontroller-to-microcontroller communication
• Serial debugging and data transfer
• Educational and STEM projects

Package Contents

• 1 × HC-05 Bluetooth Module
• 1 × Six-pin breakout board with button

Important Notes

• The HC-05 uses Bluetooth Classic, not Bluetooth Low Energy.
• The module transfers serial data and does not stream Bluetooth audio.
• HC-05 RXD uses 3.3V logic.
• Add a voltage divider or level shifter between a 5V controller TX pin and HC-05 RXD.
• Default settings may vary slightly between firmware versions.